Stator vane stage actuated by a rotary actuator ring moved by electric motor means

Abstract

A variable-pitch stator vane stage in which the vanes are moved by a rotary actuator ring driven by an electric motor. The outer actuator ring is connected by cranks to the vanes and is constrained to move in rotation only, centered on the axis of the turbomachine; the drive system includes two coaxial portions, an inner portion secured to the casing and an outer portion including the actuator ring, with an electrical drive unit being arranged between the two portions.

1. A variable-pitch stator vane stage comprising vanes arranged in a casing, said vanes being moved by a drive system comprising an actuator ring outside said casing and carried thereby, with said actuator ring being connected to the vanes of said stage by cranks in order to actuate them simultaneously, wherein said actuator ring is constrained to move in rotation only, centered on the axis of said turbomachine, said drive system comprises two coaxial portions, an inner portion secured to the casing and an outer portion comprising said actuator ring that is connected to said cranks, and that is guided in rotation about said inner portion, and wherein at least one electrical drive unit is arranged between the two portions, wherein said outer portion and said actuator ring move together relative to said inner portion and said casing. 
   
   
     2. A variable-pitch stator vane stage arranged in a casing, said variable-pitch stator vane stage comprising vanes movable by a drive system comprising an actuator ring outside said casing and carried thereby, with said actuator ring being connected to the vanes of said stage by cranks in order to actuate them simultaneously, wherein said actuator ring is constrained to move in rotation only, centered on the axis of said turbomachine, said drive system comprises two coaxial portions, an inner portion secured to the casing and an outer portion including said actuator ring that is connected to said cranks, and that is guided in rotation about said inner portion, and wherein at least one electrical drive unit is arranged between the two coaxial portions,
 wherein said inner portion comprises a stationary annular rail projecting from the outside surface of said casing, coaxially thereabout, and said outer portion comprises, in addition to said actuator ring, at least three moving equipments circumferentially spaced apart and constrained to move along said rail, and wherein each moving equipment is coupled to said actuator ring by a radial guide arrangement, and said drive unit is arranged between one of the moving equipments and said inner portion. 
 
   
   
     3. A vane stage according to  claim 2 , wherein said drive unit is a linear electric motor that is shared structurally between said inner portion and said moving equipment. 
   
   
     4. A vane stage according to  claim 2 , wherein said drive unit comprises a stepper electric motor and rack-and-pinion gear means arranged between the shaft of the motor and one of said inner or outer portions, the body of said motor being carried by the respective other outer or inner portion. 
   
   
     5. A vane stage according to  claim 4 , wherein said motor is carried by the casing and wherein said rack is carried by said moving equipment. 
   
   
     6. A vane stage according to  claim 4 , wherein said motor is carried by said moving equipment and wherein said rack is secured to the outside surface of said casing. 
   
   
     7. A vane stage according to  claim 2 , wherein said outer portion comprises at least four moving equipments that are circumferentially spaced apart, and wherein two similar drive units are engaged between said inner portion and two respective substantially diametrically opposite moving equipments. 
   
   
     8. A vane stage according to  claim 3 , wherein, for each drive unit, said actuator ring includes a connection bridge in the form of a sector of increased radius of curvature, shaped to leave a space housing the moving equipment of said corresponding drive unit. 
   
   
     9. A vane stage according to  claim 8 , wherein said radial guide arrangement corresponding to said moving equipment of said drive unit is mounted between said moving equipment and the adjacent connection bridge. 
   
   
     10. A compressor provided with at least one variable-pitch stator vane stage according to  claim 2 . 
   
   
     11. A turbomachine including at least one compressor according to  claim 10 .